Iran has refused an offer from the United States to join a global alliance preparing to combat Islamic State militants, according to Iran's supreme leader, Ayatollah Ali Khamenei.

Khamenei said Monday that the US offered to discuss a coordinated
effort with Iran against Islamic State (IS, also known as ISIS or
ISIL), a common foe in the region, in the midst of an escalating
campaign of violence that continues to claim lives across Iraq in
Syria.

“The American ambassador in Iraq asked our ambassador (in
Iraq) for a session to discuss coordinating a fight against Daesh
(Islamic State),” said Khamenei, the state-run Islamic
Republic News Agency reported, according to Reuters.

“Our ambassador in Iraq reflected this to us, which was
welcomed by some (Iranian) officials, but I was opposed. I saw no
point in cooperating with a country whose hands are dirty and
intentions murky."

According to the Washington Post, Khamenei took issue with what
he referred to as Washington's “evil
intentions.”

Khamenei said his rejection came prior to Washington’s public
exclusion of Iran in Monday’s conference of foreign ministers in
Paris, where a coalition of international diplomats have
congregated to discuss possible strategies against the jihadist
group. Host nation France had wanted to invite Iran, the Post
reported.

US Secretary of State John Kerry has said Iran’s presence in
Paris would not occur based on the Islamic Republic’s support of
its ally Syria in the nation’s civil war against Western-backed
rebels. US State Department spokeswoman Jen Psaki reiterated that
Washington was opposed to any military partnership with Iran.

“Now they (the US) are lying, in saying that it is them who
excluded us from their coalition, while it was Iran that refused
to participate in this collation to begin with,” said
Khamenei, who on Monday had just left a hospital following
prostate surgery.

Khamenei pointed to previous US-led military incursions in the
Middle East as reason to believe the US is only looking out for
its own interests.

"American officials' comments on forming an anti-Islamic
State (alliance) are blank, hollow and self-serving, and
contradictions in their behaviors and statements attest to this
fact," said Khamenei.

"The Americans should keep in mind that if they go ahead with
such a thing, then the same problems that they faced in Iraq in
the past 10 years will come back.”

He added that Washington wants in Iraq what it had in Pakistan,
"a playground where they can enter freely and bomb at
will.”

Despite the public denunciations from both sides, State Dept.
spokeswoman Psaki did not rule out a potential partnership with
Iran at a later date.

“We will be continuing those talks on the nuclear issue later
this week in New York,” Psaki said, according to the Post.
“There may be another opportunity on the margins in the
future to discuss Iraq.”

The ongoing, US-dominated negotiations regarding Iran’s nuclear
program were the pretext last year for the first
conversation between a US president and Iranian leadership in
30 years. US President Barack Obama and Iranian President Hassan
Rouhani discussed “our ongoing efforts to reach an agreement
over Iran's nuclear program,” Obama said following the phone
conversation.

Meanwhile, in Paris, Arab, European, and other diplomats began
talks about supporting the new Iraqi government and slowing
momentum of Islamic State.

“Islamic State’s doctrine is either you support us or kill
us,” Iraqi President Fouad Massoum told representatives of
30 countries attending the Paris conference. “It has
committed massacres and genocidal crimes and ethnic
purification.”

The conference comes after Sec. Kerry’s week-long tour of Arab
allies and Turkey where he attempted to recruit diplomatic and
military support for campaign against IS.

Persian Gulf states Saudi Arabia and United Arab Emirates have
reportedly
volunteered to conduct airstrikes alongside US forces. The
Saudis have also pressured the US to give Syrian rebels
surface-to-air antiaircraft weapons, but the Obama administration
has thus far refused.

Islamic State militants currently controls large swaths of Syria
and neighboring Iraq. Formerly affiliated with Al-Qaeda, IS is
one of many opposition groups fighting President Bashar Assad’s
forces - and each other - in Syria.

So-called moderate rebels fighting in Syria have a problematic
track record despite the US government’s ongoing reliance on
their efforts. The United States has supported these rebels with
both lethal
and non-lethal aid, lending to fears that arms sent with the
help of the Gulf states were channeled to the likes of IS.

A study
released last week found that Islamic State fighters are
using captured US weapons given to moderate rebels in Syria by
Saudi Arabia, a longstanding enemy of Assad’s Syria and his ally
Iran.

US allies in the Gulf region have fostered
groups like IS in Syria’s civil war, as
elite donors from the likes of Saudi Arabia, Kuwait and Qatar
have pumped money into destabilizing foes in the region.

President Obama has pledged
to use airstrikes against IS strongholds in the region. He
emphasized Wednesday that the US will not hesitate to take direct
military action against terrorists in Syria and Iraq to
"degrade ISIL’s leadership, logistically and operational
capability, and deny it sanctuary and resources to plan, prepare
and execute attacks.” Obama’s plan will be scrutinized on
Capitol Hill in Washington this week.

On Monday, White House press secretary Josh Earnest told
reporters during a daily briefing that the Obama administration
is “gratified” by what he said was significant
bipartisan support so far from Congress for the president's plan
against IS. However, Earnest added that the US would not be
coordinating any military action with Iran.

"The thing that we have been really clear about is the US
does not coordinate military action or share intelligence with
Iran, and we don't have any plans to do so," Earnest said,
while at the same time acknowledging that representatives from
both countries may indeed have had conversations on the sidelines
concerning the Islamic State militants.